Optical deflecting device and image forming apparatus using the same

An image forming apparatus, comprising:

• a light source;
• an optical deflecting device including (i) a supporting member, (ii) an oscillating member and (iii) a driving member for driving said oscillating member, wherein said oscillating member includes a first movable element and a second movable element torsionally oscillating about a common torsion axis, a first torsion spring for coupling said first movable element and said supporting member with each other, and a second torsion spring for coupling said first and second movable elements with each other and having a torsion axis the same as said first torsion spring, and wherein said first movable element is formed with a void configured to avoid blocking of incident light being incident on said second movable element from a direction intersecting with said torsion axis;
• and
• a photosensitive member,
• wherein said light source is so disposed that light is incident on a reflection surface of said second movable element, from a side where said void of said first movable element is present, and
• wherein said optical deflecting device deflects the light from said light source so that at least a portion of the light is incident on said photosensitive member thereby to produce an electrostatic latent image on said photosensitive member.

An optical deflecting device, comprising:

• a supporting member;
• an oscillating member;
• and
• a driving member for driving said oscillating member,
• wherein said oscillating member includes a first movable element and a second movable element torsionally oscillating about a single torsion axis, a first torsion spring for coupling said first movable element and said supporting member with each other, and a second torsion spring for coupling said first and second movable elements with each other,
• wherein said first torsion spring and said second torsion spring are disposed along a single straight line, and
• wherein said first movable element is formed with one of (i) a void which extends from a side near said torsion axis to a side remote from said torsion axis and totally penetrates a material of said first movable element to define a apace and (ii) a void which defines a space while leaving there a part of the material at the side remote from said torsion axis, said first movable element being disposed to surround said second movable element.